1. Field of the Invention
The present invention relates to an engine starter circuit for an automotive vehicle provided with an automatic transmission, and more specifically to an engine starter circuit such that an engine can be started only when the gear selector lever has been securely shifted into the park position.
2. Description of the Prior Art
In an automotive vehicle provided with an automatic transmission, when a gear selector lever is shifted into any position of Park (P), Reverse (R), Neutral (N), Drive (D), Second (2), or First (1), the position of transmission gears is changed to drive or park the vehicle under an appropriate gear ratio. Therefore, in order to start the engine safely, it is necessary to start the engine after the driver confirms that the gear selector level has been shifted into either the park position (P) or the neutral position (N). If the engine is started when the selector lever is in any selector lever positions other than the park position (P) or the neutral position (N), the vehicle will move dangerously when the engine starts.
In order to securely start the engine only when the gear selector lever is shifted into the park position or neutral position, conventionally there is provided an inhibitor switch including a park-position detection switch turned on only when the gear selector lever is shifted into the park position and a neutral-position detection switch turned on only when the gear selector lever is shifted into the neutral position.
In a prior-art engine starter circuit, however, since the above-mentioned inhibitor switch is usually positioned with respect to a linkage mechanism so as to be usable in common with a control switch for actuating necessary hydraulic-pressure control valves for the torque converter and there inevitably exists mechanical play in the linkage mechanism used as the inhibitor-switch actuating mechanism, there will often be a pseudo-park or pseudo-neutral position in which the inhibitor switch is turned on even when the gear selector lever is not securely shifted into the park or neutral position, that is, when the gear selector lever is within a deviation angle range near the correct park or neutral position.
In order to reduce this angle range of the pseudo-park or pseudo-neutral position, it is possible to use a strong detent mechanism; however, when the switching force is increased for further reliable positioning of the selector lever, the gear selector lever becomes difficult to operate, that is, it is impossible to completely eliminate the deviation angle range of pseudo-park or pseudo-neutral position.
A more detailed description of the prior-art engine starter circuit for an automotive vehicle provided with an automatic transmission will be made hereinafter under DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS with reference to the attached drawings.